How to make resin coasters – resin coaster tutorial

How to make resin coasters

Originally written July 2016.  Updated December 2019.

by Kate Ledum

If you are looking for an easy and fun way to make a handmade gift, then making resin coasters is for you!  Making small resin charms from other projects, then including them in a new project like this resin coaster DIY, is a great way to double the handmade fun.  This project is going to show you the fun of using resin leaves and shells you have already made in how to make resin coasters.

And don’t worry if you are asking yourself how to make resin coasters without making your own resin charms.  You can do it with found objects as well!

resin coasters

In the article Using Pearl Ex with Resin Two Ways we made a variety of resin leaves. We also made some shells using the same techniques. These are both perfect for including in a resin coaster.

resin leaves

Other small castings such as butterflies, ballerinas, flowers, and buttons will work great too. The items you include in the coaster should be no more than ¼” thick. The items will also need to be smaller than the coaster mold. If you’re putting in multiple items, 1-2” or smaller are recommended. The mold we’ll be using is 4” in diameter and 3/8” deep.

Supplies for your how to make resin coasters project:

• Small resin items previously cast such as leaves, shells, butterflies, buttons, etc.
Resin coaster mold
Castin’ Craft Easy Cast resin
Castin’ Craft Mold Release
1 oz re-usable graduated mixing cups
Large Graduated 10 ounce reusable mixing cups
Stir Sticks
Nitrile gloves
Resin Curing mat
Safety Glasses
• Paper dust and filter mask
• Clear dot “bumper pads”
• Cork sheet
• Craft knife
• Craft glue
• Wet wipes
• Scissors

For this resin coaster mold project, I’m using Easy Cast resin.  Easy Cast in its final cured state will be slightly softer than Resin Obsession Super Clear and faintly tinged with yellow, but that’s okay for a coaster. You can, though, use Super Clear resin for making coasters, too. Just follow the Super Clear directions for mixing the parts instead of the directions here.

I am also making two coasters slightly different from each other.

plastic coaster molds

Deciding Which Way the Coaster should face

The first thing you do for a project like this is to decide which side you want to be the top of the coaster. If you want the side facing the table to be the top, you will need to put everything in upside down. Otherwise, if you want the side facing you to be the top, then everything will be facing up. Everything facing you can be easier to arrange since you can see exactly how it is going to look. With everything facing the table, you can lift up the mold and look at it from underneath, but that can be risky while you have liquid uncured resin in it.

The inner surface on this mold is not shiny. That means the finished item will have a matte finish except where the resin is poured in. The pouring side will have a shiny finish. Knowing how the finished item will be can also help you decide.

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The coaster mold has a very gently sloped side making the diameter of the mold slightly smaller on the table side. If you make the coaster with the table side up, the top of the coaster will be slightly smaller than the bottom. If you make the coaster with the side facing you as the top, the top will be slightly larger than the bottom. Either way will work well as a coaster.

For this project on how to make resin coasters, the leaves coaster will face toward you and the shell coaster will face the table. For steps which are the same for both coasters, only the Leaves is shown.

placing leaves in a plastic mold

Deciding What to Put In the Coaster

Place the the charms you want to use into the dry mold. See how they’ll fit and how you like them placed together.

checking the fit for a coaster mold

TIP:  Since a coaster needs to be flat to do its job, you need to make sure all the items you put in the mold rise above the edge. One way to check this is to place a piece of paper across the top of the mold. As long as nothing is touching the top of the paper or poking it up, it should be fine.

checking the placement of leaves in a coaster mold

TIP: You can take a picture of how you placed your items in the dry mold to use as a guide when putting them in with the resin later.

prepping a plastic mold with a release agent

Prepare the Mold

Spray the mold liberally with the mold release and set it aside to dry for at least 30 minutes.




Prepare the resin and your work area

Before you start mixing the resin, you should put on a pair of protective gloves.

For the best results, resin likes a warm, but not hot room. 72-74F is the recommended temperature for how to make resin coasters.

warming a resin kit in a small crock pot

Warming resin in a warm water will help reduce bubbles in the mix. You can use a bowl with very warm, not hot, water or an electric salsa pot for no more than 5-10 minutes.

Easy Cast resin measured and ready to mix for resin coaster molds

Measure and mix the resin

The coaster mold we’re using holds a total of 2 ½ ounces of resin. I’m mixing a bit more than 3 ounces (100 ml) of resin for both of the molds. The marks on my resin cups are essential to making sure I get accurate measurements.

1. In one cup, pour in enough of Part A (clear liquid) to reach the 50 ml mark.
2. Pour 50 ml of Part B in a second cup.




mixing resin in a plastic mixing cup

3. Combine Part A and Part B.
4. Using a stir stick, scrape the sides of the cup while slowly stirring the resin to mix the parts. This helps to reduce the number of bubbles in your mix.
6. Scrape the side of the cup and stir stick from time to time.
7. Mix until everything goes clear, which takes about two to three minutes.
8. Then pour the mix into a third cup and mix for at least 1 minute more to ensure all of the resin is completely mixed.

pouring resin into a coaster mold

Pouring in the First Layer of Resin

Pour a small amount of resin into the mold.

rotate the mold to coat it with resin

To evenly coat the bottom of the mold, you can tip it slightly from side to side. At this point you want only about 1/8” to cover the bottom of the mold.

pouring resin into a smaller mixing cup

Adding the Leaves

For the leaves mold, we’re going to have the side of the mold facing up to be the finished top of the coaster. This means we’ll be placing the leaves so they’re facing us as we work.

Pour a small amount of resin into a small cup. Using a small cup for the next stage is much more manageable than a large one.

coating a leaf with resin

Drop one of the resin leaves into the small cup and spoon resin over it with the stir stick. Covering an inclusion with liquid resin helps to avoid trapping bubbles when putting it into the mold. The liquid on the inclusion will ‘meet’ the other liquid and flow together pushing away bubbles from under the inclusion. An inclusion is anything you’re ‘including’ in a resin casting. Resin leaves are the inclusion for this coaster.

adding a resin leaf to a resin casting

Once it’s coated with liquid resin, pick the leaf up with your stir stick and slip it into the mold, into the thin layer of resin.

Position leaf in resin casting

Be careful not to trap any bubbles beneath the leaf as you move it into position.

adding leaves to a resin coaster

Add more resin leaves, first bathing each in resin. Use your stir stick to move them around in the mold as desired.

leaves in a resin casting

Continue adding leaves. If you took a picture earlier when you were dry fitting them in the mold, you can use it now to arrange them similarly. Push down the leaves to make as flat a surface as possible. Make sure you do not have any leaves poking up higher than the sides of the mold. You can use the paper across the top now, too, but be careful not to dip it into the resin. Getting resin on the paper won’t ruin the casting, but it will make your paper unusable.

TIP: While placing leaves, you can carefully pick up your mold and, without tipping it, you can look at it from the bottom though the clear plastic to see if you trapped any big bubbles. If you did, now is the best time to deal with them.

pouring resin into a coaster mold

Pouring on Additional Resin

After you have arranged the leaves, you want to pour in enough resin to cover them but not so much that it overfills the mold. Pour the resin to about 1/8” below the lip of the mold. Use your stir stick to push down any of the leaves that are too high or that might have decided to float.

shells in a resin mold

Shells Mold

Going back over to the shells mold. For this mold, we’re going to have the side facing the table as the finished top of the coaster.

Repeat Step 5 above in our project on how to make resin coasters to add a thin layer of resin to this mold as well. For this mold, since we’ll be adding in some rounded items, make that first layer about 1/4” to have a bit more liquid for the shells to sit in.

Just as with the leaves, coat each shell with resin before you put it into the mold. Place the shells so their back is facing you. If you have other resin shells than the ones we cast in the first tutorial, you can add them as well.

Once you have the shells placed, like the leaves mold, pour in additional resin but stop at about 1/4” from the top so we can add a ‘sand’ level later. If any of the shells is above the line of the resin, when we add the ‘sand’, they’ll look sunk in a bit rather than sitting on the ‘sand’.

using a heat tool to pop bubbles in resin

Popping Bubbles

To help reduce the inclusion of bubbles in the resin, you can use a heat tool (such as one used for heat embossing on cards) or lighter to encourage bubbles to rise to the top. Many bubbles will pop on their own. You might have to use a toothpick or the edge of a clean stir stick to encourage bubbles congregating on the sides to pop. When you have inclusions in the resin, it’s doubly important to follow this step as bubbles can get trapped in the shapes.

Just as with the leaves, coat each shell with resin before you put it into the mold. Place the shells so their back is facing you. If you have other resin shells than the ones we cast in the first tutorial, you can add them as well.




Leave to cure

Cover your molds and wait for the resin to cure. It is always best to cover your curing resin because you don’t want dust or cat hair or other unwanted things to become part of your project.

With Easy Cast, the cure time to unmolding is a minimum of 12 hours after the last resin was added.

shells in a resin coaster

Add Sand to the Shells Coaster

We’re going to give the shells some sand to ‘sit’ on. Since we’re building the coaster from the front to the back, we have to add the back when there won’t be any chance of it sinking down to become part of the front of the finished piece.

After the Shells coaster has been curing at least 4-5 hours (if you’re using Super Clear, at least 2-3 hours), the resin should be firm but can be sticky. This is a soft cure stage and a good time to add more since it will stay ‘behind’ everything we included earlier.

TIP: You can do this step after the first layer is fully cured for exactly the same effect. The two layers of resin will create a permanent bond.

shells in a resin coaster

Before adding the next layer is also a good time to flip over the mold and look through the clear plastic to get an idea how the coaster will look. Do not remove the coaster from the mold and be careful not to break the seal at this time. If there is air between the cured resin and the mold, the new resin will flow into that space and ruin the project.

add resin to shells coaster

To add another layer, we have to mix up a brand new batch of resin. Since this is going to be a small area, we can use the small cups and mix up just an ounce of Easy Cast. Make no less than the minimum recommended by the instructions that came with the resin.

Like we did before, pour a thin layer of resin on to the soft cured resin. Be sure to get the backs of each of the shells wet with the new resin. This will help reduce bubbles and get the next layer where we want it.

pouring resin into a smaller mixing cup

For this project, I was going to use real sand but didn’t have any on hand (or rather couldn’t find the sand I am sure I still have stashed somewhere) so I made faux sand from mixing a couple colours of Pearl Ex and adding in some chunky glitter. Real sand would work the same way as this faux sand.

Pour a small bit of the resin into another cup. You don’t want to just dump the sand into your main mixing cup because you want to have more control over how much resin and how much sand you’re combining. Plus, if you dump the sand in to the main cup, if you have resin left over, you can’t really do anything else with it.




mixing sand with resin

Add the sand to the second cup and, with a second stir stick, slowly stir to combine the sand with the resin. Try not to introduce bubbles into the mixture. When the sandy resin is ready, it will look a lot like watery mud or a slurry.

adding sandy resin to a coaster

Pour the sandy resin into the mold over the shells.

resin and sand in a coaster mold

Continue filling the mold with sand and resin until it is about 1/8” from the top edge. This helps to avoid overfills. If there are still bits sticking up, don’t worry. There are a couple more steps left.

Just as before, use a heat tool to pop any bubbles and then set the coaster to cure

unmolding a resin coaster

Removing the Coaster from the Mold

After more than 12 hours after the last resin pour, the coaster should be ready to unmold. Remember that we poured additional resin into the Shells coaster. It will be ready to unmold later than the Leaves coaster. When using Easy Cast, I usually wait until the next day to unmold.

Carefully bend the mold a little to start a line of air around the edge of the mold. You can press from the centre back of the mold as well. Continue lightly bending the mold until you can lift part of the coaster free. Because we used mold release at the start, the coaster should come out without a lot of effort.

resin coasters tutorial

When you bend a plastic mold to release cured resin, you don’t want to twist it so hard it bends out of shape, just enough to break the seal between the mold and the cured resin. Sometimes a whack on a hard surface, like a desk, can help break the seal, just like when you need to break the seal on a new jar of jam. A single whack is usually enough. If the seal still doesn’t want to break, you can put the mold with the stubborn resin into the freezer for 10-15 minutes. When you take it out, give it a whack on the counter or desk. Once you start to see a bubble of air between the mold and the cured resin, you’ve won.

cutting the edge of resin

Finishing the casting edge

When you cast in a mold and don’t fill to the absolute top of the edge or dome, the resin will cure ever so slightly concave. This will leave a sharp and potentially uneven edge all around that’s difficult to show in pictures but your fingers will definitely feel it.

You can carefully cut away the majority of the sharp edge with a sharp pair of scissors. The resin is pretty thin in this location and can be simply cut away. Make sure you cut around the mold evenly.

sanding edges of a resin coaster with a nail file

You can also sand the edge. A nail sander from the dollar store works great because it’s an easy shape to hold in your hand and the sanding surface is not too coarse. You generally don’t want anything coarser than 400 grit.

Be sure to wear safety glasses any time you are sanding resin. It’s also best to wear a paper breathing mask to avoid inhaling any of the resin dust.

checking to see if a resin coaster is flat

Sanding the coaster

After taking off the edge, you should do a ‘tip test’ to see how flat the coaster is to determine what other steps we might need to do.

Put a water bottle or cup on the resin and try to tip the item from side to side. If it doesn’t rock, then the coaster is flat enough. If it does rock, you’ll need to do something to make it flatter, either add a small coating of more resin, similar to doming, or sand off the bits that stick out.  This is an important nuance in how to make resin coasters.

shells raised above surface of the resin coaster mold casting

On the Shells coaster, a couple of the shells extend further than the ‘sand’ layer. This can be detected in the tip test and also just by looking from the side. Since the bottom of the shells are sticking out the back, let’s sand them down a bit.

sanding a coaster on wet/dry sandpaper

When sanding a large area of resin, not only can it create a large amount of resin dust, but the friction can heat up the resin and cause some melting. Sand the coaster in a pool of water to accommodate this. A cheap foil pan works well.

WARNING: If any item is used with uncured or resin dust, it is unsafe to use it with food after.

To sand evenly, move it over the sand paper in a figure eight.  Check the edge to make sure it’s smooth to the touch as well..

Only sand to flatten on the back side of your coaster. If you need to flatten the top and want to preserve the inclusions that might be protruding a little, you can add a small layer of resin similar to a doming technique.

cutting a cork base

Adding a cork base to the resin coaster

Since the shells coaster of our how to make resin coasters project has an opaque bottom, this is a perfect time to add a cork bottom. It will also be less likely to scratch any surface. You could use felt for this instead if you prefer.

Trace the mold on to the cork with a pen or pencil and then cut it out on the inside of the line.

applying glue to cork

Slather the cork disc with craft glue. Be sure to get the glue out to the edges and not too thick.




gluing cork onto a coaster bottom

Place the cork disc to the back side of the coaster and press firmly to adhere well.

bumper pads for coaster

Adding clear dots to the coaster base

After the leaves design of our how to make resin coasters project is fully cured, we can finish it, too.

To preserve the clear look of the coaster, we’ll add some clear dots to the bottom. This will help prevent the coaster from scuffing surfaces and keep it from moving. You can buy bumper pads at hardware or craft stores.  They are usually in the area of hardware for hanging pictures or cabinet doors.

Resin coaster with bumper pads

Most bumper pads are self-adhesive. Simple peel them off and stick them where you want. Since I’m want a clear look on the leaves coaster, I placed them behind the opaque leaves. You want the pads to be evenly spaced so the coaster doesn’t rock when something is placed on it.

Resin coaster tutorial

Finished resin coasters

Ta da! We now have two coasters from our how to make reisn coasters project made with resin items we cast earlier.  It was fun making two styles using the same coaster mold. This how to make resin coasters tutorial covered a lot of techniques too while learning how to make them.

Unpublished Blog Posts of Resin Obsession, LLC © 2020 Resin Obsession, LLC

34 Comments

Vickie

Awesome I am going to make these with guitar picks for my husband and his friend.

Reply
Hale

hi, how is your spray? what’s are made of? or what can we use for mold?

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katesi

Does resin stick to glass? I have an idea for something similar but I want a free form edge so I’m looking for a surface to pour on. Would putting the mold release on a glass surface be enough?

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Katherine Swift

Resin sticks to glass. Using a mold release will help, but I can’t guarantee it will work.

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soona

Looks amazing! I have sunflowers growing and I was thinking of cutting some of the heads and making a few coasters for my grandparents. Is mold release absolutely necessary with silicone molds or does it just make it easier to remove?

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Beth

I have been making coasters with resin, but am running into the problem that when a mug with hot coffee/water whatever is placed on the coaster it leaves a ring on the coaster that doesn’t come off. What can you do to prevent this or stop this?

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Beth

I use Famowood that is supposed to be for bars and such and is heat resistant to 110 degrees and Easy Cast.

Reply
Renée

Hi there,
I would also like to know what resin to use to avoid “heat rings” from hot beverages being set on coasters. Please don’t forget about us!
Please advise!
Thanks,
Renée

Reply
Annette

Regarding the checking for bubbles on the underside – in order to keep the mold stable – could you move the mold (after the pour) onto a piece of plexiglas or glass so that you could easily pick it up and look at the bottom side of the mold?

Reply
Kate

I’m wanting to make a resin coaster with a river running through it. How can I separate these spaces so the colors don’t blend throughout? Any suggestions would be great, I’ve never done any resin work before.

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Judy M

How do you keep drinks from sticking to the coasters? I’ve got them nice and flat, but drinks are sticking if the glass has any condensation on it.

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Barbara

I am trying to do a small desk top. I covered it with small shells and a few larger ones that I want to stick out a bit . I covered with polyurethane resin but it wasn’t enough . Later I covered with another thicker layer but I could not have been so careful it has not dried. What do I do ? Plus it still needs more. Advice please. I had nobody to advise me from the beginning.

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Cathy Duke

I would like to pour resin into a baked polymer clay ring dish. I would like to submerge a small dried flower from my father’s funeral into the resin. Which type of resin do you suggest?

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Brittney

Do you recommend pre-coating ALL accessories on resin before adding to the coaster?

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Brittney Rivera

thank you! I’m so excited to receive my order and get started! I ordered some dolls to take apart, inspired by your monster high bracelet.

Also, can you direct me to another blog that explains how to keep insertions from tipping?

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Katherine Swift

Yeah! Can’t wait to see your doll bracelet.

I’m not sure I understand what you mean by ‘insertions from tipping’. Can you tell me more?

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Brittney Rivera

Sure! I’m not hip with resin lingo, so my apologies for the confusion!

I tested a bangle bracelet with small metal gear charms. Instead of staying the in the positions in which they were placed, they leaned forward or backward in the mold. Is there a way to prevent that? I used an epoxy resin.

Adele Sasson

Did you get an answer about insertions? I’d like to know too.
Thanx

marilena

Whenever I make coasters, even though they appear nice and dry and smooth, the glasses stick to them. Even if they are empty with no hot or cold liquid in them.Apparently, many resiners have the same problem.

Reply
Brittney

Hi Adele! I didn’t. I’ve abandoned bracelets and am perfecting coasters. What I’ve learned, and is probably relevant to the tipping problem, is two things: wall building or waiting. If you want an inclusion to sit a certain way, it has to be supported by a cured wall of resin. I’ve also learned that waiting 30-40 minutes, before inserting, let’s the resin thicken. At that point, you just have to be diligent about keeping things upright until the resin cures to where it’s just about gel. Perhaps YouTube has the answer!

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